Illness usually catches an otherwise healthy person by surprise. You suddenly come down with flu-like symptoms – or a child falls and there is a bleeding wound. Most often these things happen at inconvenient times when routine health services are closed. This is the time to turn to your home medicine cabinet, the contents of which might help you to avoid a trip to your GP or A&E.

As a GP, I see lots of people with minor, self-limiting illnesses. They are often surprised when I suggest they pop to the local pharmacy without the need for a prescription. I warn patients not to waste their money on fancy brands and packaging for painkillers. Where possible, people should buy the generic rather than the branded version of the drug. The big offender is Nurofen, which can cost 10 times more than generic ibuprofen.

Pharmacists are good at giving practical advice on common ailments and will refer on when they feel GP input is required. However, not all pharmacists will offer you the cheapest unbranded version of the drug, unless you ask for it. So here are my tips for which items to stock, and the best deals I found on my local high street.

Painkillers and fever-reducing medicine

If you keep only one thing in your medicine cabinet, it should be paracetamol and/or ibuprofen. These drugs have a dual action – they relieve pain and reduce fever. Use them for common viruses with fever, aches, pains and sprains.

Paracetamol is the safest – though you must not take more than the recommended daily dose. It is one of the few drugs that is safe for pregnant women to take.

Ibuprofen is a very effective painkiller because it has anti-inflammatory action, although not everyone is able to take it. If you have asthma or problems with your stomach, it is best you speak with your doctor first.

Thermometer

Distinguishing between a child who may simply feel hot to touch or a child with a raging fever is difficult but clinically important. Digital thermometers are the most accurate. However, fever scan strips that you place on the forehead are easier to use. While not so accurate, they do give an indication of whether the child has a temperature and where on the scale it is.

What you should buy

Anti-itch medication

Small rashes following insect bites can be very itchy. Applying some anti-itch cream or taking an antihistamine tablet can relieve symptoms. People not known to have hay fever who experience allergy symptoms of an unknown cause may also get relief from taking an antihistamine.

Anti-acid medication

Heartburn, the sensation of acid coming up from your stomach is unpleasant and may be precipitated by a spicy meal or a heavy night on the town. Taking Gaviscon or the drug ranitidine, which work to neutralise and reduce acid symptoms, for a few days can often be enough to resolve the problem. If symptoms persist, you should seek medical advice.

What you should buy

Sore throat medication

Ninety per cent of sore throats are caused by viruses, which means there is only treatment available to ease rather than cure the symptoms. If paracetemol and/or ibuprofen aren't helping much, throat lozenges, particularly those that contain local anaesthetic, can ease the symptoms.

What you should buy

• Sore throat dual-action lozenges £1.99 for 24, Superdrug.

Treatment for cuts and grazes

Fancy first-aid kits are expensive, and all that is needed for many minor cuts and grazes is salty water to clean the wound, some sterile gauze and tape or plasters. If there is a small open wound, sticky, thin strips of special closure tape can be applied to bring the skin together and avoid an unnecessary trip to A&E.